Multi-phase or multi-component materials where solid and fluids are combined (slurries and suspensions, for example) may be separated into the respective solid, semi-solid, or fluid components and subcomponents thereof. Complex multi-component materials may be difficult to separate because of particle sizes, fluid viscosities, interactions between the materials, etc. Depending on the desired end use of a subcomponent, separation of some multi-component materials may be too labor intensive or time consuming to warrant separating the materials.
For example, in arthroplasty procedures, the materials removed from the subject during bone bed preparation or bone reaming include a mixture of cartilage, bone chips, surrounding blood and fluids, and the dense spongy material known as bone marrow. The bone reaming materials can include beneficial undifferentiated cells, such as mesenchymal stem cells, white blood cells, and platelets which may be used to expedite the healing of the injury site and incision or may be used as therapy in other procedures. To separate the bone reaming materials into the beneficial mesenchymal stem cells is a multi-step process and can occupy hours of preparation and waiting time. An exemplary separation process includes precipitating the unwanted cells via culturing, plating, incubating the preparation, and then washing and centrifuging the preparation several times to concentrate the desired stem cells. This process is time consuming, labor intensive, and inefficient—characteristics that are neither desirable in a self-paced laboratory environment, nor desirable under surgical conditions and time restraints. Accordingly, despite the vast applications of the undifferentiated cells, white blood cells, and platelets in bone reaming material, the extensive labor in separation is too burdensome and therefore, the bone reaming material or bone reaming “debris” is discarded.
Whole blood and fluids from the arthoplasty procedure may also be discarded despite the beneficial components. Like the bone reaming material, these fluids have fractions that may be used to expedite healing and promote tissue health. For example, the whole blood may be separated into platelets, red blood cells, and plasma by density in a device such as a centrifuge. Nonetheless, these methods do not provide a simple or efficient method to extract any more than one fraction and especially a fraction other than the top fraction. Even in these systems, multiple spins may be required to effectively separate the constituents without commingling the sample. These same difficulties may be encountered even using systems incorporating a float or other device that is disposed within the sample at the interfaces of the different fractions during the centrifuge process. Additionally, the current separation systems are generally designed to separate only same phase components and do not work with multiple states of matter such as partial fluid mixtures which contain macroparticles or large sized particles, such as the bone reaming materials described above.
Therefore, it is desired to provide a device to allow for collection of selected constituents from a multi-component material having macroparticles. It is desired to provide a device to allow for the easy and reproducible removal of a particular fraction which does not happen to be the top fraction of a sample. It is desired to remove the required sample without mixing the different fractions during the extraction process. In addition, it is desired to provide a device which allows for a consistent extraction of known volumes or concentrations of the fraction elements. Moreover, it is desired to separate and concentrate a multi-state composition with one centrifugation step.